Hyperthermic effects of hand bathing: benefits of incorporating finger flexion-extension exercise

[Purpose] The purpose of our study was to compare the effects of hand bathing using plain water and water supplemented with inorganic salt and carbonated gas and to assess the hyperthermic effects of performing finger flexion-extension exercise while bathing in water with carbonated gas and inorganic salt and without water. [Subjects and Methods] Sixteen healthy, young males were subjected to plain water bathing, CO(2) bathing, kineto-CO(2) bathing, or no bathing. CO(2) bathing involved bathing in a solution of artificial bath additives including inorganic salts and carbon dioxide. Partial bathing of the hand was implemented for 20 minutes at 41 °C. The concentration of carbonic gas was set at 33 ppm. In the kineto-CO(2) bathing condition, finger flexion-extension exercise was performed at 60 laps per minute in the same solution used in CO(2) bathing. The control group engaged in the same exercise as those in the kineto-CO(2) bathing group, but without bathing. [Results] A significant increase in deep-body temperature was observed in the CO(2) bathing and kineto-CO(2) bathing conditions compared with both the plain water bathing and control condition. [Conclusion] Significantly heightened hyperthermic effects were observed when finger flexion-extension exercise was performed during CO(2) bathing.